The invention relates to a belt tensioner for a seat belt system.
In general, for checking the functional safety of belt tensioners both the Intended use, i.e. the use of the belt tensioner in the mounted state in the vehicle in the case of crash, and the not intended use, e.g. undesired triggering during production, during transport etc., have to be taken into account. These different load cases are based on different loading states.
Virtually all known construction modes of pyrotechnic belt tensioners show undesired variation in the webbing retraction performance in different loading states, for the components of a belt tensioner sometimes present a strongly different behavior in dependence on the external circumstances, especially In respect of temperature and component tolerances.